Printed circuit board

Abstract

To provide a printed circuit board that can increase the degree of freedom in wiring while suppressing a decrease in noise shielding effect.SOLUTION: The conductor of a printed circuit board include a signal wiring 231 that constitutes a signal conductor, a signal via 232 that constitutes the signal conductor and is connected to the signal wiring 231, and a plurality of ground vias 242 that are provided so as to surround the signal via 232. The plurality of ground vias 242 are arranged in an equiangular spiral such that the angle formed between any two adjacent ground vias 242 and the signal via 232 is a predetermined angle.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The disclosure herein relates to printed circuit boards. [Background technology]

[0002] Patent Document 1 discloses a printed circuit board having a signal via and a plurality of ground vias arranged around the signal via. The contents of the prior art document are incorporated by reference as an explanation of the technical elements in this specification. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5088135 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, multiple ground vias are arranged at predetermined intervals (equal intervals). As a result, some of the ground vias must be removed in order to draw signal wiring from the signal vias. This creates areas where no ground vias are arranged, reducing the effectiveness of shielding noise propagating from the signal vias toward the side of the board. In terms of the above and other aspects not mentioned, further improvements are required in electronic devices.

[0005] An object of the present disclosure is to provide a printed circuit board that can increase the degree of freedom in wiring while suppressing a decrease in noise shielding effect. [Means for solving the problem]

[0006] The printed circuit board according to one embodiment of the present disclosure comprises: An insulating substrate (21); a conductor (22) disposed on an insulating substrate; Equipped with The conductor has a signal wiring (231) constituting a signal conductor, a signal via (232) constituting the signal conductor and connected to the signal wiring, and a plurality of ground vias (242) provided so as to surround the signal via; The plurality of ground vias are arranged in an equiangular spiral such that the angle formed between any two adjacent ground vias and a signal via is a predetermined angle.

[0007] In the disclosed printed circuit board, multiple ground vias are arranged in an equiangular spiral pattern. This allows the distance between two adjacent ground vias to increase as they move away from the signal via. This increases the degree of freedom in wiring while suppressing a decrease in noise shielding effectiveness.

[0008] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims are intended to exemplarily indicate the corresponding parts of the embodiments described below, and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing an example of an electronic device including a printed circuit board according to a first embodiment. [Figure 2] FIG. 1 is a cross-sectional view showing an example of a printed circuit board. [Figure 3] FIG. 10 is a diagram showing an example of the arrangement of ground vias. [Figure 4] FIG. 1 is a diagram showing the basic configuration of a model used in a total radiated power simulation. [Figure 5] FIG. [Figure 6] FIG. 10 is a diagram illustrating a first reference example. [Figure 7] FIG. 10 is a diagram illustrating a second reference example. [Figure 8] FIG. 10 is a diagram showing the results of a total radiated power simulation. [Figure 9]FIG. [Figure 10] FIG. [Figure 11] FIG. [Figure 12] 10 is a diagram showing an example of the arrangement of ground vias in a printed circuit board according to a second embodiment. FIG. [Figure 13] FIG. 10 is a diagram showing an example of the arrangement of ground vias in a printed circuit board according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, several embodiments will be described with reference to the drawings. Note that in each embodiment, corresponding components are designated by the same reference numerals, and redundant description may be omitted. When only a portion of the configuration is described in each embodiment, the configuration of another embodiment previously described may be applied to the remaining portion of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of several embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0011] (First embodiment) The electronic device described in this embodiment can be applied to, for example, a mobile body. The mobile body can be, for example, a vehicle, an air vehicle such as a drone or an electric vertical take-off and landing aircraft (eVTOL), a ship, a construction machine, an agricultural machine, etc. eVTOL is an abbreviation for electronic Vertical Take-Off and Landing aircraft. An example in which the electronic device is applied to a vehicle will be described below. Note that the electronic device may also be applied to applications other than a mobile body.

[0012] <Electronic equipment> First, the schematic configuration of an electronic device will be described with reference to Fig. 1. Fig. 1 shows an example of an electronic device. In Fig. 1, the conductors of a printed circuit board are omitted.

[0013] In the following, the thickness direction of the printed circuit board (insulating base material) is referred to as the Z direction. The direction perpendicular to the Z direction is referred to as the X direction. The direction perpendicular to both the X and Z directions is referred to as the Y direction. The X, Y, and Z directions are positioned perpendicular to one another. Unless otherwise specified, the shape viewed from the Z direction, that is, the shape along the XY plane, is referred to as the planar shape. The planar view from the Z direction is sometimes simply referred to as the planar view.

[0014] The electronic device 10 includes a printed circuit board 20 and electronic components 30 mounted on the printed circuit board 20. The electronic device 10 includes a connector (not shown) mounted on the printed circuit board 20. The electronic device 10 may include a housing that houses at least some of the other elements that make up the electronic device 10.

[0015] The electronic components 30 are mounted on the printed circuit board 20. A plurality of electronic components 30 are mounted on the printed circuit board 20. The electronic components 30 are generally arranged on at least one of the upper surface 20a and the lower surface 20b of the printed circuit board 20. At least a portion of the electronic components 30 may be embedded in the insulating base material 21. The illustrated electronic components 30 are arranged on the upper surface 20a. The number of electronic components 30 is not limited to the example shown in FIG. 1 .

[0016] The electronic component 30 forms a circuit together with the conductors 22 provided on the printed circuit board 20. The example electronic component 30 includes components that constitute a processing circuit, a power supply circuit, a communication circuit for high-speed signal transmission, and the like. The electronic component 30 includes a semiconductor chip on which a switching element such as a MOSFET is formed. MOSFET is an abbreviation for Metal Oxide Semiconductor Field Effect Transistor.

[0017] The electronic device 10 is an electronic control unit (ECU). ECU is an abbreviation for electronic control unit. The arithmetic processing circuit includes a processor, RAM, storage, etc. RAM is an abbreviation for Random Access Memory. The processor includes, for example, a CPU, etc. CPU is an abbreviation for Central Processing Unit. The processor is coupled to the RAM, and by accessing the RAM, the electronic device 10 (electronic control unit) executes various processes to realize each function. The storage includes a non-volatile storage medium such as a flash memory. The storage stores a control program executed by the processor.

[0018] <Printed circuit board> Next, a printed circuit board will be described with reference to Figures 2 and 3. Figure 2 shows an example of a printed circuit board. Figure 2 shows a cross section along the signal wiring and signal via. Solder resist is omitted from Figure 2. Figure 2 also shows a high-frequency source. Figure 3 shows the arrangement of multiple ground vias surrounding a signal via. Figure 3 shows an example of the routing (routing) of signal wiring connected to a signal via. For convenience, the signal wiring and ground vias are shown on the same side in Figure 3 to show their positional relationship.

[0019] The printed circuit board 20 may also be referred to as a board, a wiring board, or the like. The planar shape of the printed circuit board 20 is not particularly limited. The illustrated printed circuit board 20 has a substantially rectangular shape when viewed in plan in the Z direction. The printed circuit board 20 includes an insulating substrate 21 and a conductor 22 disposed on the insulating substrate 21. The insulating substrate 21 is formed using an electrically insulating material such as resin. The insulating substrate 21 may contain only resin, or may be a combination of resin and glass cloth, nonwoven fabric, or the like.

[0020] The conductor 22 is formed using a metal material with good conductivity, such as Cu. The conductor 22 includes wiring. The wiring may be referred to as a conductor pattern, a wiring pattern, a wiring layer, or the like. The wiring may be formed, for example, by patterning a metal foil, or by printing. In addition to wiring, the conductor 22 may include a through-hole land or a via conductor. The through-hole land is formed on the wall surface of a through-hole that penetrates the printed circuit board 20 in the Z direction. The via conductor is formed by disposing a metal, such as plating, in a through-hole (via) formed in an insulating layer that constitutes the insulating base material 21. The via conductor electrically connects, for example, wiring arranged on different layers.

[0021] The printed circuit board 20 is a multilayer board. The conductors 22 (wiring) are arranged in multiple layers on the insulating base material 21. The conductors 22 may include wiring arranged in a surface layer on the upper surface 20a side of the insulating base material 21, or may include wiring arranged in a surface layer on the lower surface 20b side. The conductors 22 may also include wiring arranged inside the insulating base material 21. The conductors 22 have a signal conductor 23 and a ground conductor 24.

[0022] The signal conductor 23 is a conductor that transmits signals. The signal conductor 23 is a communication line used for high-speed communication such as CAN, LVDS, GVIF, and Ethernet. CAN, GVIF, and Ethernet are registered trademarks. CAN is an abbreviation for Controller Area Network. LVDS is an abbreviation for Low Voltage Differential Signaling. GVIF is an abbreviation for Gigabit Video Interface. The signal conductor 23 is a wiring that can generate common mode noise. The signal conductor 23 can generate high-frequency common mode noise, for example, due to the switching operation of electronic components 30 (semiconductor chips) mounted on the printed circuit board 20.

[0023] The signal conductor 23 has a signal wiring 231 and a signal via 232. The signal wiring 231 extends in the XY plane. The signal via 232 extends in the Z direction. The signal via 232 is a via conductor electrically connected to the signal wiring 231. The signal via 232 electrically connects the signal wirings 231 arranged on different layers. In the illustrated printed circuit board 20, the signal wirings 231 are arranged on the first and third layers. The first layer is the surface layer on the top surface 20a side.

[0024] The ground conductor 24 provides a reference potential (board ground) for the printed circuit board 20. The ground conductor 24 functions as a return path for common mode noise (noise current). The ground conductor 24, together with the signal conductor 23 and a high-frequency source, forms a closed noise circuit. The ground conductor 24 shields unnecessary electromagnetic noise that accompanies signal transmission. The ground conductor 24 includes a ground layer 241 and a ground via 242.

[0025] The ground layer 241 is a wiring having a larger area than other wiring in order to provide a reference potential. The ground layer 241 is sometimes referred to as a solid ground. The ground layer 241 may be arranged on only one layer different from the signal wiring 231, or may be arranged on multiple layers different from the signal wiring 231. In the illustrated printed circuit board 20, the ground layer 241 is arranged on the second and fourth layers. The fourth layer is a surface layer on the lower surface 20b side.

[0026] The ground layer 241 is arranged so as to overlap at least a portion of the signal wiring 231, preferably the entire length thereof, in a plan view. The ground layer 241 exhibits a shielding effect due to image current. The ground layer 241 mainly shields electromagnetic noise caused by the transmission signal of the signal wiring 231. The ground conductor 24 may have a ground layer 241 arranged on the same layer (common layer) as the signal wiring 231, in addition to a ground layer 241 arranged on a different layer from the signal wiring 231.

[0027] The ground vias 242 extend in the Z direction. The ground vias 242 are via conductors electrically connected to the ground layer 241. The ground vias 242 are via conductors arranged to surround the signal vias 232. The ground vias 242 mainly shield electromagnetic noise caused by the transmission signals of the signal vias 232. The multiple ground vias 242 surrounding the signal vias 232 form a so-called shield wall. In the illustrated printed circuit board 20, one end of the ground via 242 is connected to the second ground layer 241, and the other end is connected to the fourth ground layer 241.

[0028] 3, the multiple ground vias 242 are arranged in an equiangular spiral such that the angle θ between any two adjacent ground vias 242 and the signal via 232 is a predetermined angle. The multiple ground vias 242 are arranged around an axis that coincides with approximately the center of the signal via 232 and is approximately parallel to the Z direction. Because the angle θ between two ground vias 242 and the signal via 232 is equiangular (a constant angle), the interval between two adjacent ground vias 242 is not constant. The interval between the ground vias 242 is narrower as they are closer to the signal via 232 and wider as they are farther away from the signal via 232.

[0029] The interval is the distance (shortest distance) between the centers of adjacent ground vias 242. The interval between two adjacent ground vias 242 is equal to or less than ¼ wavelength of the frequency of the signal transmitted through the signal via 232 (signal conductor 23) in the insulating substrate 21 (printed circuit board 20). Similarly, the distance between the signal via 232 and the ground via 242 is equal to or less than ¼ wavelength in the insulating substrate 21. For example, at 3 GHz, it is 6.25 mm or less.

[0030] It is preferable to route the signal wiring 231 so that it is drawn out from between the ground vias 242 whose spacing between adjacent ground vias 242 is equal to or greater than the median value. More preferably, as illustrated in Fig. 3, it is preferable to draw out the signal wiring 231 from between the first ground via 2421 and the second ground via 2422. The first ground via 2421 is the ground via 242 that is the shortest distance from the signal via 232. The second ground via 2422 is the ground via 242 that is located next to the first ground via 2421 and that is the longest distance from the signal via 232.

[0031] 3, the signal wiring 231 is drawn out from the signal via 232 so as to cross an imaginary line VL connecting the first ground via 2421 and the second ground via 2422. In FIG. 3, the imaginary line VL is indicated by a dashed line. The distance L1 between the first ground via 2421 and the second ground via 2422 is the longest distance between any two adjacent ground vias 242. The signal wiring 231 is drawn out from between the ground vias 242 (2421, 2422) having the widest distance.

[0032] The illustrated ground vias 242 are arranged in a logarithmic spiral. The logarithmic spiral is defined by Equations 1 to 5. a is the distance between the signal vias 232 and the ground vias 242, i.e., the radius. The angle θ between the two ground vias 242 and the signal via 232 corresponds to θ0. For example, at 3 GHz, a=1.5 mm, θ0=20 degrees to divide the entire circumference into 18 equal parts, and n=0 to 17. Taking the two-dot chain line shown in FIG. 3 as the reference position and considering it counterclockwise, for example, the first ground via 2421 where the two-dot chain line intersects has n=0, and the second ground via 2422 located next to the first ground via 2421 has n=17. In the XY plane, the x and y coordinates of the signal via 232 are (0, 0). The x and y coordinates of the ground via 242 when 0≦θ<π are calculated using Equations 2 and 3. The x and y coordinates of the ground via 242 in the range of π≦θ<2π are determined by Equations 4 and 5.

[0033]

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[0034] In the case of a logarithmic spiral, as shown in Fig. 3, there are two sets of first ground vias 2421 and second ground vias 2422. In Fig. 3, the signal wiring 231 is drawn out from between the first set of first ground vias 2421 and second ground vias 2422. Alternatively, there may be a signal wiring 231 drawn out from between the first set of first ground vias 2421 and second ground vias 2422, and a signal wiring 231 drawn out from between the second set of first ground vias 2421 and second ground vias 2422.

[0035] <Shielding effect of ground vias> Next, the shielding effect of an equiangular spiral arrangement will be described with reference to Figs. 4 to 8. Fig. 4 shows the basic configuration of the model used in the total radiated power simulation. Fig. 5 shows an example (this example) in which ground vias are added in a logarithmic spiral shape to the basic configuration shown in Fig. 4. Fig. 6 shows a first reference example. Fig. 7 shows a second reference example. Fig. 8 shows the results of the total radiated power simulation. In Fig. 8, the solid line shows the results of this example, the dashed line shows the results of the first reference example, and the dashed line shows the results of the second reference example.

[0036] Three models were compared in a simulation of the total radiated power from a printed circuit board. As shown in Figure 4, each model has a basic configuration with multiple ground vias 243 arranged in a grid pattern with a 10 mm pitch. The ground vias 243 are separate from the ground vias 242 surrounding the signal vias 232. Specifically, a total of 104 ground vias 243 are arranged in 13 columns in the X direction and 8 rows in the Y direction. Each model has a closed circuit including a signal wiring 231, two signal vias 232, a second ground layer 241, a high-frequency source, etc. The ground layer 241 was arranged on the second and fourth layers, and the signal wiring 231 was arranged on the third layer. The signal vias 232 were arranged in the fourth and tenth columns, midway between the fourth and fifth rows. The signal wiring 231 was configured to extend in the X direction.

[0037] The three models further include a plurality of ground vias 242 surrounding the signal via 232 in addition to the basic configuration. The printed circuit board 20 of the first model (this example) shown in Figure 5 has a plurality of ground vias 242 arranged in a logarithmic spiral. As with Figure 3, the logarithmic spiral arrangement of the ground vias 242 has a radius a of 1.5 mm and the entire circumference is divided into 18 equal parts. Eighteen ground vias 242 are arranged for one signal via 232.

[0038] 6 has four ground vias 242 for one signal via 232. The ground vias 242 are arranged at the vertices of a square with each side having a length of 5 mm and the signal vias 232 located at the intersections of the diagonals.

[0039] 7 has a plurality of ground vias 242 arranged in a perfect circle. The ground vias 242 are arranged in a circle with a radius of 5 mm, and the circle includes two ground vias 243. Sixteen ground vias 242 are arranged for one signal via 232.

[0040] 8, it is clear that this example can suppress the total radiated power from the printed circuit board more effectively than the first reference example in which the adjacent ground vias 242 are equidistant from the signal via 232 and the interval between them is wider. It is also clear that this example can suppress the total radiated power to the same extent as the second reference example in which the adjacent ground vias 242 are equidistant from the signal via 232 and the interval between them is narrower than the first reference example.

[0041] <Summary of the First Embodiment> In the printed circuit board 20 of this embodiment, the conductor 22 has a signal wiring 231 that constitutes the signal conductor 23, a signal via 232 that constitutes the signal conductor 23 and is connected to the signal wiring 231, and a plurality of ground vias 242 that are provided so as to surround the signal via 232. The plurality of ground vias 242 are arranged in an equiangular spiral so that the angle formed between any two adjacent ground vias 242 and the signal via 232 is a predetermined angle.

[0042] When the ground vias 242 are arranged in an equiangular spiral in this way, the distance between two adjacent ground vias 242 increases as they move away from the signal via 232. This allows the signal wiring 231 to be drawn from a position with a wider distance. Furthermore, there is no need to remove (thin out) some of the ground vias 242 in order to draw the signal wiring 231. As a result, it is possible to increase the degree of freedom in wiring while suppressing a decrease in noise shielding effect.

[0043] As shown in the example, the signal wiring 231 may be drawn out from between two adjacent ground vias 242 where the spacing between the two adjacent ground vias 242 is equal to or greater than the median value. The spacing between two adjacent ground vias 242 becomes wider the farther away from the signal via 232 in the equiangular spiral arrangement. Therefore, by drawing out the signal wiring 231 from between the ground vias 242 where the spacing is equal to or greater than the median value, the signal wiring 231 can be drawn out without difficulty. In other words, the degree of freedom in wiring can be further improved.

[0044] As shown in the example, the signal wiring 231 may be drawn out so as to cross an imaginary straight line VL connecting the first ground via 2421, which is closest to the signal via 232, and the second ground via 2422, which is located next to the first ground via 2421 and is farthest from the signal via 232. Since the signal wiring 231 is drawn out from between the ground vias 242, which are spaced the widest apart, the degree of freedom in wiring can be further improved.

[0045] As shown in the example, the distance between two adjacent ground vias 242 may be equal to or less than ¼ wavelength of the frequency of the signal transmitted through the signal via 232. This makes it possible to prevent electromagnetic noise from leaking out between the adjacent ground vias 242.

[0046] As shown in the example, multiple ground vias 242 may be arranged in a logarithmic spiral. A logarithmic spiral is a type of equiangular spiral, and therefore can achieve the above-mentioned effects. Since the distance between the first ground via 2421 and the second ground via 2422 is wide, the degree of freedom in wiring can be improved. Since there are multiple pairs of first ground vias 2421 and second ground vias 2422, the degree of freedom in wiring can also be improved in this respect.

[0047] <Modification> 9, a shield wall for the signal wiring 231 may be provided by combining a plurality of ground vias 242 arranged in a logarithmic spiral with another ground via 244 different from the ground vias 242. This can provide a noise shielding effect for both the signal wiring 231 and the signal via 232.

[0048] Although an example has been shown in which the signal wiring 231 is drawn from between the first ground via 2421 and the second ground via 2422, this is not limiting. For example, as shown in Fig. 10, the signal wiring 231 may be drawn from between the ground vias 242 whose spacing is equal to or greater than the median. In Fig. 10, the signal wiring 231 is drawn from between the ground vias 242 whose spacing is the third widest. Although not shown in the figure, in the first model used in the simulation, the signal wiring 231 is drawn from between the ground vias 242 whose spacing is the fifth widest, that is, between the ground vias 242 whose spacing is the median.

[0049] The ground vias 242 surrounding the signal via 232 may be arranged in an equiangular spiral. For example, a 360-degree range surrounding the signal via 232 may be covered by one continuous ground via group, or may be shared by two ground via groups as illustrated in FIG. 3. In FIG. 3, two ground via groups share the range at 180 degrees each. Alternatively, the range may be shared by three or more ground via groups. For example, as illustrated in FIG. 11, the range may be shared by four ground via groups. In FIG. 11, four ground via groups share the range at 90 degrees each. In the example illustrated in FIG. 11, the dashed signal wiring 231 and the solid signal wiring 231 are on different layers. Note that in any adjacent first and second via groups among multiple ground via groups, the angle formed by the ground via 242 at the end of the first via group on the second via group side and the ground via 242 at the end of the second via group on the first via group side, and the signal via 232, is also a predetermined angle. In other words, the angle formed by two adjacent ground vias 242 and a signal via 232 that are configured across adjacent via groups is also subject to equiangularity.

[0050] (Second embodiment) This embodiment is a modification of the preceding embodiment as a basic form, and the description of the preceding embodiment can be used. In the preceding embodiment, a logarithmic spiral is shown as an example of an equiangular spiral. Instead of this, a Bernoulli spiral may be adopted.

[0051] 12 shows an example of the layout of ground vias in the printed circuit board according to this embodiment. Fig. 12 corresponds to Fig. 3.

[0052] In the printed circuit board 20, the ground vias 242 surrounding the signal via 232 are arranged in a Bernoulli spiral. The Bernoulli spiral is a type of equiangular spiral. The Bernoulli spiral is defined by Equation 1, Equation 6, and Equation 7. As with a logarithmic spiral, a is the distance between the signal via 232 and the ground via 242, i.e., the radius. b is a proportionality constant. For example, at 3 GHz, a = 1.5 mm, and θ = 20 degrees, n = 0 to 17, and b = 1.2 to divide the entire circumference into 18 equal parts. Taking the two-dot chain line shown in FIG. 12 as the reference position, considering the counterclockwise direction, for example, n = 0 for the first ground via 2421 where the two-dot chain line intersects. In the XY plane, the x and y coordinates of the signal via 232 are (0, 0). The x and y coordinates of the ground via 242 when 0≦θ<π are calculated using Equation 6 and Equation 7.

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[0054] 12, the signal wiring 231 is drawn out from the signal via 232 so as to cross the imaginary line VL connecting the first ground via 2421 and the second ground via 2422. The signal wiring 231 is drawn out from between the ground vias 242 with the widest spacing. The other configurations are the same as those shown in the preceding embodiment.

[0055] <Summary of the second embodiment> As shown in the example, the ground vias may be arranged in a Bernoulli spiral, which is a type of equiangular spiral and can therefore achieve the above-mentioned effects.

[0056] Although an example has been shown in which the signal wiring 231 is drawn out from between the first ground via 2421 and the second ground via 2422, the present invention is not limited to this. The signal wiring 231 may also be drawn out from between the ground vias 242 whose spacing is equal to or greater than the median value.

[0057] In the above-described Bernoulli spiral arrangement, the 360-degree range surrounding the signal via 232 may be shared by multiple groups of ground vias.

[0058] (Third embodiment) This embodiment is a modification of the preceding embodiment, and the description of the preceding embodiment can be used. In the preceding embodiment, a logarithmic spiral and a Bernoulli spiral are shown as examples of equiangular spirals. Alternatively, a Bernoulli double spiral may be used.

[0059] 13 shows an example of the layout of ground vias in the printed circuit board according to this embodiment. Fig. 13 corresponds to Fig. 3.

[0060] In the printed circuit board 20, the multiple ground vias 242 surrounding the signal via 232 are arranged in the shape of a Bernoulli double helix. The Bernoulli double helix is ​​a type of equiangular spiral. The Bernoulli double helix is ​​defined by Equations 8 to 12. a1 is the radius of the first helix, and a2 is the radius of the second helix. b is a proportionality constant. For example, at 3 GHz, a1 = 1.5 mm, a2 = 2 mm, and n = 0 to 17 and b = 1.2 to divide the entire circumference into 18 equal parts. Taking the two-dot chain line shown in FIG. 13 as the reference position, considering the counterclockwise direction, for example, the first ground via 2421 where the two-dot chain line intersects has n = 0, and the second ground via 2422 located next to the first ground via 2421 has n = 17. The x and y coordinates of the first ground via 242 in the range 0≦θ<2π are calculated using Equations 9 and 10. The x and y coordinates of the second ground via 242 in the range of 0≦θ<2π are calculated by Equations 11 and 12.

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[0062] 13, the signal wiring 231 is drawn out from the signal via 232 so as to cross the imaginary line VL connecting the first ground via 2421 and the second ground via 2422. The signal wiring 231 is drawn out from between the ground vias 242 having the widest spacing. The other configurations are the same as those shown in the preceding embodiment.

[0063] <Summary of the third embodiment> As shown in the example, the plurality of ground vias may be arranged in the form of a Bernoulli double spiral, which is a type of equiangular spiral and can therefore achieve the above-mentioned effects.

[0064] Although an example has been shown in which the signal wiring 231 is drawn out from between the first ground via 2421 and the second ground via 2422, the present invention is not limited to this. The signal wiring 231 may also be drawn out from between the ground vias 242 whose spacing is equal to or greater than the median value.

[0065] In the above-described Bernoulli double spiral arrangement, the 360-degree range surrounding the signal via 232 may be shared by multiple groups of ground vias.

[0066] (Other embodiments) The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0067] The disclosure in the specification, drawings, etc. is not limited by the claims. The disclosure in the specification, drawings, etc. encompasses the technical ideas described in the claims, and extends to more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being bound by the claims.

[0068] When an element or layer is referred to as being "on," "coupled," "connected," or "bonded," it may be directly on, coupled, connected, or bonded to another element or layer, and intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly coupled," "directly connected," or "directly bonded" to another element or layer, no intervening elements or layers are present. Other terms used to describe relationships between elements should be construed in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). As used in this specification, the term "and / or" includes any and all combinations of one or more of the associated listed items. That is, reference to A and / or B means at least one of A and B.

[0069] Spatially relative terms such as "inside," "outside," "back," "below," "low," "top," "top," and the like are used herein to facilitate the description of one element or feature's relationship to other elements or features, as illustrated. Spatially relative terms may be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures were turned over, elements described as "below" or "directly below" other elements or features would then be oriented "above" the other elements or features. Thus, the term "bottom" can encompass both an orientation of top and bottom. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in this specification would be interpreted accordingly. [Explanation of symbols]

[0070] 10...electronic equipment, 20...printed circuit board, 20a...Top surface, 20b...Back side, 21...insulating substrate, 22...conductor, 23...signal conductor, 231...signal wiring, 232...signal via, 24...Ground conductor, 241...Ground layer, 242, 243, 244...Ground vias, 2421...first ground via, 2422...second ground via, 30...Electronic components

Claims

1. An insulating substrate (21); a conductor (22) disposed on the insulating substrate; Equipped with The conductor includes a signal wiring (231) constituting a signal conductor, a signal via (232) constituting the signal conductor and connected to the signal wiring, and a plurality of ground vias (242) provided so as to surround the signal via; A printed circuit board, wherein the plurality of ground vias are arranged in an equiangular spiral such that the angle formed between any two adjacent ground vias and the signal via is a predetermined angle.

2. The printed circuit board according to claim 1 , wherein the signal wiring is drawn out from between two adjacent ground vias whose spacing between the two adjacent ground vias is equal to or greater than a median value.

3. 3. The printed circuit board of claim 2, wherein the signal wiring is drawn out from the signal via so as to cross an imaginary straight line connecting a first ground via (2421) among the plurality of ground vias that is the shortest distance from the signal via, and a second ground via (2422) that is located next to the first ground via and the longest distance from the signal via.

4. The printed circuit board according to any one of claims 1 to 3, wherein the distance between two adjacent ground vias is equal to or less than 1 / 4 wavelength of the frequency of the signal transmitted through the signal via in the insulating substrate.

5. 4. The printed circuit board according to claim 1, wherein the plurality of ground vias are arranged in a logarithmic spiral.

6. 4. The printed circuit board according to claim 1, wherein the plurality of ground vias are arranged in a Bernoulli spiral.

7. 4. The printed circuit board according to claim 1, wherein the plurality of ground vias are arranged in a Bernoulli double spiral.

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